The primary purpose of this new study is to test an ancestry informative marker (AIM) set for use in America, however the results are of general interest, as they surveyed much of South America, from Chile to Venezuela.
J. M. Galanter et al., Development of a Panel of Genome-Wide Ancestry Informative Markers to Study Admixture Throughout the Americas. PLoS Genetics 2012. Open access.
They selected a group of AIMs from Native American populations from Mexico, Peru and Bolivia and used Mestizo samples, together with others from Europe and Africa in order to refine their AIM set. Then they proceeded to test it in South American samples of Mestizo, Afroamerican and Native American self-identification.
The result is synthesized in figure 6:
|Purple and red tags indicate American samples used in the generation of the AIM set|
There is some more information in the text and figures of the paper, which you may find an interesting read.